Impregnating webs, cloths and fabrics



' P 1932- E. SCHNAB'EL ET AL 1,852,065

I IMPREGNATING WEBS, CLQTHS, AND FABRICS Filed A ril 11. 1930 PatentedApr. 5, 1932 UNITED STATES.

PATENT OFFICE. f

EHIL SCHNAIBEL, or DEBSAU IN ANHAL'IE, .AND FRIEDRICH A. w minim, orMANN- nam, GERMANY, assmnoas TO I. a. raannnmpns mm AKnENeEsELLscnu'r,or rRANxronr-oN-rnE-mim', GERMANY IMPREGNATING wEBs, cLo'rns A NDFABRICS Application filed 11 1111 11, 1930, Serial No. 443,439,]:11111in Germany March -1, 1929.

Our present invention relates to a process 10 special table andlapplyingthe impregnating solution thereon from above by means of an atomizer ora, pouring device. This process presents the disadvantage ofallowing-only ,part of the air bubbles contained inthe web to escapeupwardly in consequence of the high viscosity of the impregnatingsolution, so that the impregnated web, when the imiregnating liquor hassolidified, contains air ubbles.

According to our present invention, 1mpregnated webs free from airbubbles, are obtainable in a simple manner by removing the air containedin the web of fibrous mamediately before the impregnating liquor'isapplied on to the web. This removal of the air and: the impregnation ofthe web-can also be carried out in one working operation; This can bedoneb applying theimpreg- 'nating liquor from elow and thus utilizing..the solvent vapors evolved by the liquor itself. The impregnatingliquor penetrating ,into the web from below' is preceded by a layer ofsolvent vapors driving out. the air, enclosed in the interstices betweenthe single fibers," in an upward direction and thus ensures a completeimpregnation of the web Also if the. vapor tension of the impregnatingliquor be only relatively small, the air is practically completelydriven out from the web because, by the action of the impregnatingliquor which rises from below, it is forced upwardly where it may freelyescape.

terial by means of'solvent vapors before the without any air bubblesbeing left therein.

I Furthermore, the new impregnating procoss may be completed, if,desired, by applying, according to known methods,'a jfurtherimpregnating liquor on the upper surface of the web beforetheimpregnating liquor.- applied totho lower surface has been dried. Forthis PHIPO'SQ either'the same or another impregnating liquormay be used.

The process can be conducted with the aid of all devices which allow theimpregnating liquor to be carried to the lower surface'of the web offibrous material. however, a known drumor a band pouring Preferably,

machine is used, in which the impregnating liquor is poured, by means ofa film-casting tunnel havinga slitiof corresponding breadth on:r'uniformly moving solid support which is p'rovidmlwith guide-devices.for the web. These guide-devices,v for instance, suitable rollers or thelike, lead; the web to the exitslit of the film-casting funnel or. to aplaceimmediately behind it, so that the web to be impregnated liesclosely on the layer-of impregnating liquor flowing out ofthefunnel. Theweb .can be guided to the film-casting .slit. for instance, in such amanner that'itis caused to slide downwardly at the front wall of thefunnel, while lying closely and uniformly on the inner side thereof andthen. to reach the conveyer bandor the drum car-.

rying the impregnating liquor, se l {that it lies closely on theoutflowing liquor. Since,

when simply guiding the web through the funnel, the danger exists thatit is prematurely soaked with the liquor and thea-ir bubbles driven outthereof enter the. latter, it is recommendable to provide for thisprocess a particular funnel having a double front'wall through which theweb passes without touching the impregnating liquor before the exit of'the'liquor supplying device.

which preferably maybe used. I

The web I to. be impregnated is reeled ofi ed, the web is guided overrolls to the slit- Fig. l of the drawing diagrammatically illustratesour new process and the apparatus of a film-casting'funn'el C arrangedabove the conveyer band G of a film-casting machine.

Fig. 2 shows an embodiment of the funnel in section. The impregnatingliquor- F is filled into the film-casting funnel C from, which it flowsto the conveyer band G through the slit H. The funnel Chas a doublefront wall formed by the plates E and D through which the web I isguided to the slit H of the funnel C, which may be adjusted by means ofa hand wheel K. The plates D and E are parallel to each other anddistanced, so that the web to be impregnated may be guided through theformed interstice.

The process of impregnating may also be performed with the use of a filmcasting funnel not provided with a double front wall, by guiding, forinstance, the web by means of rollers closely in front of the slit ofthe funnel.

After having passed the outlet H of the funnel. C, the conveyer band Gis covered with a thin layer of the impregnating liquor which on theforward movement continuously enters the web I lying closely thereon.

The webs to be impregnated may be woven fications and equivalents asfall within the scope of the appended claim.

What we claim is A device for impregnating webs, cloths and fabricscomprising a support for the material to be impregnated and a funnel forcasting a uniform layer of the impregnating solution on the saidsupport, a double front wall on said funnel for guiding the material tobe impregnated and for imposing it on the layerof impregnating solutionformedimmediately at the exit of the said funnel.

In testimony whereof, we aflix our signatures.

EMIL SCHNABEL. FRIEDRICH A. W. KI'JHNE.

of animal or vegetable, natural or artificial fibers as, for instance,cotton, wool, silk, jute, ramie, nettle, artificial silk and so on.

As an impregnating compound, we may use cellulose derivatives, naturalor artificial resins, guttapercha, balata, caoutchouc, and so on, ormixtures of these products, if necessary, with addition of oils,softening or filling agents, pigments or dyes. In preparing theimpregnating liquids, we may use the organic solvents, known in the art,preferably acetone, benzene or halogenated hydrocarbons.

The thickness of the layers to be applied to the webs may vary between 1to 3000 11.,P18ferably, layers of about 50 a and more are produced.Obviously, the thickness depends upon the concentration of theimpregnating liquid and on the opening of the film-casting funnel. Thetemperature of the impregnating liquid may be varied within wide limits;the same holds true with regard to the suport on which the layer ofimpregnating iquid is cast. Too high temperatures, however, arepreferably avoided. By a suitable selection of the solvent, temperature,concentration and viscosity of' the impregnating liquor, any desiredimpregnation, free from air bubbles, may be performed. Thelayer appliedto the web may be dried by warming the support carrying it or by blowingwarm air over the impregnated fabric. These specific details and therecovery of the solvents likewise are well known from the industrydealing with the manufacture of celluloid films or oilcloth.

Numerous other embodiments of our in-' yentlon are possible and wecontemplate as included within our lnventlon all such modi

